I have previously devised methods and systems for maximizing the recovery of livestock feed values from animal wastes wherein the solids and liquids are separated from the wastes and treated so as to be suitable for introduction to the feed of the livestock as supplements. For example, in U.S. Pat. No. 3,982,499, there is disclosed a system in which animal wastes are flushed from a confinement feed area and initial separation of solids and liquids is performed by a screen filter. Liquids are forcibly removed from the solids by a pressure roll acting against a conveyor belt in an endless loop configuration after being filtered through a screen. The liquids thus separated are introduced to an aeration tank and combined with aerobic material and hydrolized so as to be usable for subsequent flushing of the confinement feeding area. Overflow from the aeration tank is further filtered through a wedge wire screening device and introduced to an additional aeration tank. After suitable treatment in the second aeration tank, the oxidized liquids are employed as supplements to the livestock feed water system. The solids are pressed to a predetermined moisture content and are then usable in that form as feed supplements in the animal ration.
Another closed loop system is disclosed in my U.S. Pat. No. 4,338,337 which is specifically intended for use in recycling livestock wastes into animal feed having a maximum concentration of total digestible nutrients. In that system, typically the waste material which is collected in gutters in the barns is periodically flushed into a sump or basin as a preliminary to pumping the waste materials to a separation stage. At the separator, the waste material is advanced to one end of an inclined screen having a limited mesh or opening size with the screen being inclined upwardly toward a discharge end. A shuttle-type separator suspended above the screen includes rows of scraper blades and pressure pads which cooperate in advancing the waste material across the screen and compressing the retained solids on the screen to remove a predetermined amount of moisture with a major amount of the fines from the solid waste material. The liquid so removed and a portion of the fines are then aerated and employed as a flushing agent by advancement through the gutters of the confinement facility to recover additional waste material and to carry it into an aeration tank. The solid waste material which does not pass with the liquid is separately collected and stored for subsequent use as an animal feed supplement.
Now it is proposed to provide a method of reclaiming solids for the recovery of feed supplement in a closed loop system which includes the constant harvest of high quality single cell proteins derived from the aerobic biological hydrolization of the fines which are removed by means of a compact and extremely efficient filter screen apparatus.